If I use any imaging control on a web page it's quite reasonable to expect users to post whatever they please into the control, including .bmp files, .tif files, .pdf files etc. Imaging controls like Zoomer jQueryUI control or the one which Stack Exchange uses for uploading images just display the image as an <img> object and so if the user tries to feed an unsupported image there "nothing happens" - the first control shows "in progress" animation and the one on Stack Exchange simply shows nothing.
I tried Zoomer in my web application and every other user will post .tif files and wonder "why it wouldn't work". It'd be great if the control could detect such cases and display some reasonable image.
Is there any easy way to handle such cases in imaging controls? What's the industry wide approach?